Hypokalemia category Normal Mild Moderate Severe Serum K
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• Hypokalemia category Normal Mild Moderate Severe Serum K (m. Eq/L( 3. 5 -5. 5 3 -3. 5 2. 5 -3 2. 5>
Etilogy • Poor dietary intake • Excessive renal loss • Excessive gastrointestinal loss: diarrhea, vomiting • Hypomagnesemia: Na+-K+ ATPase pump impaired • Drugs
Drug-Induced Hypokalemia • 3 Mechanisms – Intracellular potassium shifting – Enhanced renal excretion – Enhanced fecal elimination: sodium polystyrene sulfonate, phenolphthalein, sorbitol
• Intracellular potassium shifting – β 2 -Receptor agonists: epinephrine, salmeterol – Theophylline – Caffeine – Insulin overdose
• Enhanced renal excretion – Diurtics: loop, thiazides – High dose penicillins: penicillin, ampicillin – Mineralocorticoids miscellaneous: aminoglycosides, amphotericin B, cisplatin
Treatment • 3. 5 -4 m. Eq/L → – Nonpharmacologic therapy: dietary intake of K-rich foods • 3 -3. 5 m. Eq/L → – Nonpharmacologic/Pharmacologic therapy • Underlying cardiac conditions that predispose them to cardiac arrhythmias • Receiving concomitant digoxin therapy • < 3 m. Eq/L should keep K 4 -4. 5 m. Eq/L
• Pharmacologic therapy – Oral potassium supplementation – Intravenous potassium supplementation • severe K depletion • intolerant to oral supplementation
Calculation • m. Eq = mg x valency/(Formula weight ) • กรณของ KCL 10% หมายถง สารละลาย 100 m. L ม K 10 g • MW KCl = 39. 1 + 35. 4 = 74. 5 • K valency =1 • จากสตรคดเปน = 10 x 1000/74. 5 = 134 m. Eq/100 m. L • ดงนน 15 m. L ม K = (134 x 15)/100 = 20 m. Eq
• (10% KCl Elixer (20 m. Eq/15 ml • Ped KCl (2%) (4 m. Eq/15 ml( Product 10% KCl (20 m. Eq/15 ml) bidqid Bottle (60 ml) 80) 1 m. Eq( Increasedserum K (m. Eq/L) 0. 3 -0. 8 160) 2 m. Eq( 240) 3 m. Eq( 0. 4 -1. 6 0. 6 -2. 4
• Every 1 m. Eq/L ↓K below 3. 5 m. Eq/L = total body potassium deficit of 100 -400 m. Eq • ��� 40 -100 m. Eq of K → mild-moderate K deficits • Doses up to 120 m. Eq of K → severe K deficits
• Reference – Joseph T. Di. Piro, Robert L. Talbert, Gary C. Yee, Gary R. Matzke, Barbara G. Wells, L. Michael Posey. Pharmacotherapy A Pathophysiologic Approach. 7 th ed. New York: Mc. Graw-Hill; 2008. p. 878 -81.
